Troubleshooting HD Direct Spark Units Click here enter this application Literature:6-586.
Troubleshooting HD Direct Spark Units Enter Application
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TABLE OF CONTENTS – Definitions and Basic Operation – Call for heat and units does nothing - Green Light ON – Call for heat and units does nothing - Green Light OFF – Troubleshooting Codes for Ignition Control – Unit starts but does flame does not ignite – Flame lights and shuts down within 10 seconds – Main fan / air mover does not operate – Replace control board ONLY after completing these steps – FOR ADDITIONAL HELP & LIVE OPERATORS
DEFINITIONS & BASIC OPERATION • Soft Lockout of Control - The control does not initiate a call for heat or call for continuous fan while in lockout. The control will respond to an open limit and undesired flame. Lockout shall automatically reset after 1 hour. Lockout may be manually reset by removing power from the control for more than 1 second or removing the thermostat call for heat for more than 1 and less than 20 seconds.
FLAME STATUS - YELLOW LED LABELED “FLAME” • Flame Status LED is Lit - When flame is sensed, the flame LED is lit. • Flame LED flashes slowly - Flame current is below 1.0 uA (+/-50%), the to indicate “weak” flame. • Flame LED flashes fast - Flame is present with gas valve off. If flame is sensed longer than 4 secs while the gas valve is de-energized, the control shall energize the power exhauster and indoor blower motor.
HEATING SEQUENCE OF OPERATION • • • • • • • • • • • • Call for heat T stat contact close T stat on terminals R & W of board 24 volts from R to W terminal on board Power exhauster cycles on. 115 VAC at IND and Neutral on board. Starts pre purge cycle 24 volts through limits and pressure switch from board Short delay and then 24 volts to gas valve from board Igniter sparks Flames carries to sensing probe and proves Yellow light turns on, burner stays lit. 50 to 60 seconds later, fan motor cycles on.
END OF HEATING SEQUENCE OF OPERATION • • • • • • • • Call for heat ends Thermostat contacts open Burner flame off Yellow light turns off. Post purge on power exhauster Power exhauster cycles off. Fan motor cycles off. Green light on board stays on.
CALL FOR HEAT – UNIT DOES NOTHING • Green Light on Control Board is ON – Verify that the thermostat is wired correctly & there is a call for heat – Thermostat should be wired between R & W – If the thermostat is wired correctly and the unit still does not operate. Turn power off. Remove tstat wires. Carefully install a jumper wire between terminals R & W directly on the control board. Turn power on.
CALL FOR HEAT – UNIT DOES NOTHING • Green Light on Control Board is ON.
CALL FOR HEAT – UNIT DOES NOTHING • Green Light on Control Board is ON. Unit DOES NOT operate correctly when a jumper wire is installed between terminals R & W on the board – Check for loose connections. Disconnect and reconnect all Molex plugs. – Check to make sure there are NO troubleshooting codes – Turn the switch to the gas valve off and on.
CALL FOR HEAT – UNIT DOES NOTHING • Green Light on Control Board is OFF – There will not be a flash code – Is there 24 VAC between Sec & Com on board? Yes No Green Light Sec & Com Terminals Back Start Over
CALL FOR HEAT – UNIT DOES NOTHING • Green Light on Control Board is OFF. 24 VAC NOT present between Sec & Com on board Possible Causes Check for loose connections Check incoming power (115 VAC) If incoming power is correct, check for 24VAC at the secondary of the transformer.
CALL FOR HEAT – UNIT DOES NOTHING • Green Light on Control Board is OFF 24 VAC IS present between Sec & Com on board Possible Causes -Check fuse for blown element. Remove the fuse. Check for continuity. Do NOT just inspect element. Check for continuity. If the fuse is bad, replace fuse. -Check for loose connections -If fuse is not blown, terminal board is not letting 24 VAC through the board. Replace board.
TROUBLESHOOTING FLASH CODES • No Flashes See Green Light is off • One Flash Pressure switch does not close within 30 seconds of inducer energized.
TROUBLESHOOTING FLASH CODES • Four Flashes In lockout from failed ignition or flame loss • Five Flashes Twin communications fault • Six Flashes Open in the safety switch circuit 5 times during heat cycle (limit switch or flame roll out switch) • Seven Flashes 5 Flame losses during one heat cycle Back Start Over
NO FLASHES – TROUBLESHOOTING CODES • No Flashes Go To: Call for heat – unit does nothing Back Start Over
ONE FLASH - TROUBLESHOOTING CODES • Does the power exhauster cycle on? Yes Back No Start Over
ONE FLASH – NO POWER EXHAUSTER • Pressure switch does not close within 30 seconds of inducer energized • Unit sequence: • Green Light on, call for heat, 24 volts at R & W on board. Nothing happens. Green light will give One flash. Fan motor will not cycle on. • Possible cause: • Defective exhauster motor. Receiving 115 volts from IND and NEUTRAL terminals on board, but will not run. Replace exhauster. • Defective board. Not sending 115 volts from IND and NEUTRAL terminals to exhauster.
ONE FLASH – PRESSURE SWITCH WON’T CLOSE • Pressure switch does not close within 30 seconds of inducer energized • Unit sequence: Green light on, call for heat, 24 VAC at R & W , power exhauster cycles on, after approx. 30 seconds, Green Light will give One Flash • Possible cause: • Blockage in tubing to pressure or venting not allowing for a proper vacuum to pull pressure switch contacts closed. Troubleshoot Venting. • Wire off pressure switch • 24 VAC not coming from board.
TWO FLASHES - TROUBLESHOOTING CODES • Pressure switch is closed before inducer is energized • Unit Sequence: Green light on, call for heat, 24 volts at R & W terminal. Nothing will happen to unit operation except Green Light will give Two Flashes. • Possible Cause: • Defective or damaged pressure switch • Showing continuity between terminals in non-heat mode • The two yellow wires are showing continuity in nonheat mode.
THREE FLASHES - TROUBLESHOOTING CODES • Open in the safety switch circuit (limit switch or flame roll out switch is open) • The limit switch is ignored unless a call for heat is present (R to W energized). If the limit switch is open and a call for heat is present, the control de-energizes the gas valve, runs the blower motor, and runs the power exhauster. The control will flash “3” on the LED until the limit switch closes.
THREE FLASHES - TROUBLESHOOTING CODES • Open in the safety switch circuit (limit switch or flame roll out switch is open). • Unit sequence: • Green Light on, call for heat. Power exhauster cycles on. • Fan Motor Cycles on. Green light starts three flashes. • Possible cause: • Open or short in safety circuit (flame roll out switches some and some limit switches are manual reset). – Check for open contacts on switch in safety circuit.
FOUR FLASHES - TROUBLESHOOTING CODES • In lockout from failed ignition or flame loss • Does the unit ignition spark Yes Back No Start Over
FOUR FLASHES - TROUBLESHOOTING CODES • In lockout from failed ignition or flame loss unit DOES SPARK • Does the flame shut down within 10 Seconds Yes Back No Start Over
FOUR FLASHES - TROUBLESHOOTING CODES • In lockout from failed ignition or flame loss unit SPARKS and SHUTS DOWN within 10 seconds • Unit Sequence: • Green Light on, call for heat • Power exhauster cycles on, starts pre purge • 24 VAC present through pressure switch, limits, and to gas valve • Igniter sparks, burner cycles on for 10 seconds, then cycles off, no yellow flame light on board. Fan motor never cycles on.
FOUR FLASHES - TROUBLESHOOTING CODES • In lockout from failed ignition or flame loss unit SPARKS and SHUTS DOWN within 10 seconds • Possible Causes: • Reversed Polarity • Wire off sensor. Check for loose wires • Dirty or defective flame sensor, not sending microamps to board. Clean sensor with emery cloth. If the problem is not resolved, verify and replace sensor.
FOUR FLASHES - TROUBLESHOOTING CODES • In lockout from failed ignition or flame loss unit SPARKS and SHUTS DOWN within 10 seconds • Reversed Polarity • To check for reversed polarity. (1) Shut down all power to unit (2) Switch main incoming power lines (black and white) to unit. (3) Carefully turn main power back on to unit. • If issue is not resolved, shut off all power and return white and black wires to original positions.
FOUR FLASHES - TROUBLESHOOTING CODES • In lockout from failed ignition or flame loss unit SPARKS and SHUTS DOWN within 10 seconds • Have eliminated Reversed Polarity • Wire off sensor. Check for loose wires • Dirty or defective flame sensor, not sending micro-amps to board. Clean sensor with emery cloth. If the problem is not resolved, verify and replace sensor. • If issue is not resolved, shut off all power and return white and black wires to original positions. • Potentially defective board.
FOUR FLASHES - TROUBLESHOOTING CODES • In lockout from failed ignition or flame loss unit SPARKS but DOES NOT IGNITE • Unit Sequence: • Green light on: call for heat, 24 VAC at R & W terminals • Power exhauster cycles on, start pre purge. 24 VAC through pressure switch and limits. • Igniter sparks, no ignition, no yellow flame sense light. Will cycle 5 times in this manner, then Green light will flash four times. Power exhauster will cycle off. Fan motor will never cycle on.
FOUR FLASHES - TROUBLESHOOTING CODES • In lockout from failed ignition or flame loss unit SPARKS but DOES NOT IGNITE • Possible Causes: • • • • • • • Gas valve in “off” position No 24 VAC from board to gas valve Loose wires: wire off gas valve Excessive Inlet pressure Low or No gas pressure to inlet of valve (purge lines) Defective Gas valve.
FOUR FLASHES - TROUBLESHOOTING CODES • In lockout from failed ignition or flame loss unit DOES NOT SPARK • • • • • Unit Sequence: Green Light on, call for heat Power exhauster cycles on, starts pre purge 24 VAC power present through pressure switch, limits, and to valve No spark at igniter, RAW gas is going through orifices for approx. 6 seconds during this cycle, then cycles off, no yellow flame sense light • Will cycle 5 times in this manner. Then Green light will give four flashes.
FOUR FLASHES - TROUBLESHOOTING CODES • In lockout from failed ignition or flame loss unit DOES NOT SPARK • Possible Causes: • Loose wires: Wire off Igniter • Defective or damaged igniter. Examine, verify and replace of required.
FIVE FLASHES - TROUBLESHOOTING CODES • Twin communications fault • Occurs if the 24 VAC supply to the twins are not in phase with each other, or power is removed from one of the twins. • While a Twin Fault exists, the control does not respond to thermostat commands and flashes "5" on the status LED. Open limit and undesired flame response are still operational. The control continually tries to establish communication and automatically resumes normal operation when communication is re-established.
SIX FLASHES - TROUBLESHOOTING CODES • Open in the safety switch circuit 5 times during heat cycle (limit switch or flame roll out switch). Control goes into a hard lockout.
SIX FLASHES - TROUBLESHOOTING CODES • Open in the safety switch circuit (limit switch or flame roll out switch is open). Main air mover CYCLES ON. • • • • • Unit sequence: Green Light on, call for heat. Power exhauster cycles on. Fan Motor Cycles on. Green light starts six flashes. Possible cause: Open contacts due to over-firing of unit (flame roll out switches some and some limit switches are manual reset). – Check gas pressure. Check to make sure nothing is blocking airflow out of unit.
SIX FLASHES - TROUBLESHOOTING CODES • Open in the safety switch circuit (limit switch or flame roll out switch is open). Main air mover DOES NOT cycle on. • Unit Sequence: • Green Light on, call for heat Power exhauster cycles on, pre purge • 24 volts power present through pressure switch, limits, and to valve • Igniter Sparks, burner cycles on, yellow flame light on board is on. • After 3 to 4 minutes , unit goes out on a limit switch, yellow light off, green light will flash six times.
SEVEN FLASHES - TROUBLESHOOTING CODES • 5 Flame losses during one heat cycle • Ignition Re-Cycle - The control will re-cycle up to 5 flame losses (4 re-cycles) within a single call for heat before going to lockout. The LED will flash “7” during this lockout.
BEFORE REPLACING THE CONTROL BOARD • • • • • • • • • • • • • • • • • • • • • Remove thermostat and use a temporary jumper wire to make a call for heat Check the supply power for correct polarity Recheck all wiring to the control board for loose connections. Disconnect and reconnect all Molex plugs Recheck that the wiring to the control board matches the wiring diagram If the control board has a fuse, remove and test continuity of the fuse.
FOR ADDITIONAL HELP INSTALLATION & SERVICE MANUAL LIVE OPERATORS HD Installation and Service Manual Other Installation & Service Manuals Live Operators: 800-828-4328 Back Start Over
